The development of proper social skills requires the ability to discern and interpret social signals arising from conspecific faces as well as that to monitor their social interactions. These basic skills are abnormal in individual with autism and may account for the profound social deficits seen in autism. Studies of social visual pursuit in adolescents and adults with autism have shown atypical patterns of visual scanning of both faces and naturalistic social situations. Autistic individuals, as opposed to normal subjects, look preferentially at the mouth than the eye area of faces and neglect crucial social and communicative cues while focusing preferentially on non-social cues. Although human as well as non-human primate studies have begun to provide some information on the key components of the neural network mediating social cognition, such as the amygdala and highly interconnected midtemporal structures and the mesial prefrontal cortex, much knowledge remains to be acquired in this domain. The overall hypothesis to be tested is whether lesion of mesiofrontal-limbic structures in adult monkeys yield to abnormal face processing and visual social orientation patterns, such as those observed in autistic individuals. The specific aims of the present application are to compare visual scanning patterns 1) to still images and videotaped clips effaces of communicating primates versus that of inanimate and animate objects and 2) to videotaped clips of naturalistic social interactions between monkeys versus inanimate background distractions in intact versus operated adult monkeys who underwent mesiofrontal-limbic lesions. This innovative study will advance our knowledge of the neurobiological basis of primate social cognition, particularly perception and identification of social signals, and thus will provide critical insights into the neural dysfunctional processes seen in autism as well as significant clues for the development of new therapies. [unreadable] [unreadable]